Medical Manufacturing Frontiers: Part II

Opportunities for new and renewed products

By Robert B. AronsonSenior Editor

The first segment of our article on Medical Manufacturing Frontiers in our September 2007 issue stressed established companies that modified their existing products and processes to manufacture medical product. In this, the second segment, the emphasis is on companies that were founded specifically to develop products for the medical market.

The i-Limb Hand from Touch Bionics (Livingston, UK) is said to be a first-to-market prosthetic device with five individually powered digits. It takes advantage of technology that allows electrodes on the skin's surface to detect signals generated in the remaining portion of the patient's limb, and translate them to electronic commands that can move the hand's mechanical fingers. Users of basic prosthetic hands are reportedly able to quickly adapt to the system, and can master the device's new functionality within minutes.

Another version of the i-Limb hand's finger technology, called ProDigits, has been adapted for patients who have a partial hand. It is especially helpful to those not having fingers or a thumb to act in opposition to one another.

SmalTec International (Naperville, IL) used their industrial experience making special miniature tools to develop techniques for making end-of-wire tooling such as grippers used for surgery within the body.

Much of the company's work is on "interoperative tooling," that is, small instruments that operate inside the body. For example, one project was a catheter that was positioned within an artery using a 100 µm-diam wire. Or, as Jerry Mraz, general manager, puts it, "You-don't-have-to-open-anything" surgery.

Typically, the operations using these tools require small incisions of only 5 mm. "The emphasis on tools for small incisions is to minimize infection and reduce healing time," says Mraz.

"We are a job shop for the medical industry," explains Mraz. "We do lots of medical prototyping and R&D. And for that kind of work, cost is not often an issue."

Another important project for the company is fiber-optic connectors that may be used in some diagnostic equipment. Efficient joints between fibers are still an issue. In most cases, 70% of the signal is lost. "That is still enough for most applications, and much better than copper links, but improvements are in the works," says Mraz.

The company also makes its own brand of miniature EDMs. "It's spark technology that gives us special capabilities," he says. "This is how we can create small features on special surfaces."

SmalTec offers two machines for micro EDM and microgrinding, the EM203 and GM703. The EM203 makes holes as small as 4-µm diam as well as complex 3-D contoured shapes. Surface finishes of 10 nm Rmax or 2.8 nm RMS are possible. Maximum workpiece weight is 3.5 k and maximum dimensions are 710 mm x 835 x 810 mm.

The GM703 is a machining unit that measures 500 x 500 x 565 mm and can handle a 1.5-kg workpiece. It can deliver a surface finish of 6 nm Rmax. The machine has a 10-nm positioning resolution.

"However, our problems are not related to our production or processes but education," Mraz explains, "People do not know our technology is available."

Materialise, a large Belgian RP company, has applied its extensive RP capabilities to make parts for medical applications, and supply software for related RP equipment. They have offices worldwide, including one in Ann Arbor, MI.

One of their most popular RP software packages is Mimics 11, which focuses on improved usability and performance through enhanced algorithms for remeshing, volume rendering, and segmentation.

Mimics is a direct link to biomechanical analysis and design. With this program, the time to construct 3-D, CAD, or FEA models is reduced. It is currently used to prepare computerized data for building exact models by RP techniques. Applications include: export to CAD, finite element analysis, surgical model simulation, and RP models.

For example in a "virtual operation" using Mimics, based on CAT images from the patient, a hip implant is placed in a 3-D reconstruction of the patient's femur. With this process the operation can be visualized using real patient data, and an implant suitable for the patient's anatomy. The surgeon now knows what may be encountered during actual surgery, and plan accordingly. Another advantage is that the bone volume to be removed can be calculated in advance. The benefits are shorter operation time and more accurate surgical results.

Among the new companies that manufacture "miniature" machine tools is Microlution (Chicago). These smaller machines will be needed by manufacturers that wish to go to the next level of miniaturization and encounter problems using their "full-size" equipment. At the microscale, there are products that cannot be cast or made using EDM. They must be machined.

Microlution Inc. meets this need with their 310-S Micro-Milling machine. "It is not a shrunken conventional machine or a hobby lathe, it was designed for industrial micromachining from scratch," says company president Andy Phillip. "You have to give special attention to chip load and speed. A large motor can't accelerate and decelerate fast enough. The machine has to be light enough to minimize inertia that can reduce accuracy, but retain dynamic stiffness."

Currently this machine is designed for milling, but, it can be reconfigured for turning or used with a laser for measurement. According to Phillip, "The machine uses a palletized workholding system so the user can move work without disturbing repeatability. Software is standard, so no special operator training is needed."

Much of the company's work is in prototyping. "We are still proving the capabilities of our system. People do not know our technology is available, says Phillip."

The "camera pill" has a unique history that begins with an electro-optical design engineer working on a missile project in Israel. It was during this project that he recognized how valuable a miniature pill-sized "missile" could be for the medical field. The pill would be swallowed by a patient, and as it passed through the patient's GI tract would simultaneously transmit images along the way.

Today, the camera pill is used in a very similar way to view the small intestines and esophagus. A patient swallows the capsule with a glass of water. Then the camera sends digital images to a receiver the patient wears around his or her waist during the procedure. The images are downloaded to a computer and compiled into a video that is reviewed by the physician. During the review the physician can instantly compare the onscreen video image with known small bowel and esophageal reference images stored in the database.

The camera pill to visualize the small intestine has been in use since 2001 and the one for the esophagus has been in use since 2004. Over the course of the past several years, both the pill and its supporting Rapid software have undergone a number of upgrades. The most recent updates include next-generation camera pills (PillCam SB 2 and PillCam ESO 2) and enhanced Rapid software. These updates allow physicians to more-precisely view a patient's GI tract, and more easily diagnose disorders of the small bowel and esophagus.

New software features include improved image quality, an increase in the angle of view and viewing area, and automatic light control. The camera pill is manufactured by Given Imaging Ltd. (Yoqneam, Israel).

New products, materials, and processes are the hallmark of micromedical manufacturing. A large group of new product research efforts in the micromanufacturing area involve implantables and resorbable polymers, silicone, or titanium. Because these materials can cost from $3000-$22,000 per pound, scrap costs resulting from large runners and stamping waste have to be avoided. "Most of these products are funded through R&D efforts for medical device, aerospace, electronics, and military programs," explains Donna Bibber, President, Micro Engineering Solutions (Charlton City, MA).

Metal injection molding has become a viable alternative to CNC machining for many microparts made of stainless, titanium, and cobalt-chrome materials. At the same time, certain metal-replacement polymers are frequently used.

"Those getting into this type of work should be aware of the cost of starting a new 'micro' business unit," says Bibber. "Micro and macro scale-down is not linear or extrapolated easily so a lot of all-new equipment is often needed, along with the ability to operate it. In addition, metrology/validation for dust-speck-size features and parts requires both new equipment along with new methods for inspection."

RP Aid for Iraq

Rapid Prototyping For Baghdad is a humanitarian effort by leading companies from the RP and manufacturing industries. Designated RP4Baghdad the program has the dual goals of demonstrating a willingness to help the people of Iraq and to make the RP industry better known by the general public.

The project offers free medical support in the form of software, medical models, and medical equipment. In the difficult circumstances of a war zone, 3-D medical models are of even greater importance than in normal life. These models, made from scanned medical data, are important tools for surgeons to plan complex craniafacial operations.

The cycle can be completed in about one week. Here are the steps:

Make a 3-D CAT scan of the patient, and send the data over the internet to the US or Europe.